Mercedes-Benz OM 651 Service Manual page 36

DPF regeneration
The exhaust back pressure increases as the soot load
of the DPF increases. A sensor measures the pressure
differential upstream of and downstream of the DPF
and forwards this information to the engine control
unit. Regeneration of the DPF is initiated when the
threshold value stored there is reached.
Regeneration during driving operation is performed on
average after 800 to 1,000 km, depending on soot
emissions and filter size.
Exhaust system
1 Oxygen sensor upstream of catalytic converter
2 Oxidation catalytic converter
3 Diesel particulate filter
i Note
If DPF regeneration is not possible during normal operation, the engine diagnosis warning lamp lights up on
the instrument cluster.
– This printout will not be recorded by the update service. Status: 09 / 2008 –
If the exhaust temperature required for regeneration is
not reached during normal driving operation, selective
post injection into the combustion chambers is
performed to increase the exhaust temperature. The
regeneration procedure only takes several minutes
and depends on:
• Engine speed
• Vehicle speed
• Exhaust gas temperature
Introduction of New Generation of 4-Cylinder Inline Engines, OM 651
Exhaust system
4 Temperature sensor upstream of
diesel particulate filter
5 Rear muffler
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